|
University of
Texas Research
Research
Study Shows That Hand Washing of Cars
at Home is Harmful to Automobile Finishes
The International Carwash
Association working through a special Carwash Research Foundation Grant
to the University of Texas at Arlington, Texas, has conducted extensive
car washing tests to determine the effect on car finishes by comparing
various car washing techniques ranging from professional car washing to
the bucket and sponge used by many auto owners.
Hand washes are
extremely harmful to automobile finishes -
Tests conducted by the University of
Texas to compare surface disturbances showed that a single home hand
wash on an automobile can produce scratches that penetrate as deep as
1/10 of the total thickness of the automobile's paint.
These test findings at the
University of Texas substantiated tests done over ten years ago by the
Technical University of Munich, Germany, in association with
Mercedes-Benz, which at that time showed that similar damage was done to
an automobile when using detergent, low water volume commonly found in
hose nozzles at home, buckets of water, sponges and towels used in the
average home car washing.
Specific scientific tests at the
University of Texas further showed that hand car washing can produce so
many marks on a car's finish that they cannot even be counted. The tests
showed that in all hand washing temperatures, surface reflectance
readings steadily declined, with some hand washing techniques being
considerably worse than others. By contrast, when cars were washed by
professional full service car washes, there was virtually no change in
the surface reflectance or shine readings.
The tests showed that the average
backyard hose is not able to supply enough water along with the
detergent action to avoid damaging the car's finish. The most harmful
method of washing cars was found to be the special "car wash" brushes
that hook on to a garden hose and are purchased from local hardware
stores or automotive supply dealers. The use of this type of brush with
the low water pressure that comes out of the garden hose is the most
destructive on the finish of an automobile. The tests also showed that
techniques used at professional car washes are virtually harmless to
automobile finishes. Findings from the University of Texas research
study indicate that with the large amounts of water and specialized
detergents used in professional car washes, sophisticated gloss and
reflectance meter readings from new finishes used on automobiles were
virtually the same before and after the equivalent of several months of
normal washings in a professional car wash.
The professional car wash is able to provide and use tremendous amounts
of water along with specialized detergents and appropriate mechanical
action from cloth pads and curtains which the backyard hose and bucket
hand car wash is not able to supply. This important and interesting
research study performed by the University of Texas found that today's
automobile owner is much wiser to have their car washed by a
professional car wash, rather than washing it at home in their own
backyard.
The
Technical University of Munich has carried out an impartial scientific
comparison test in association with Mercedes-Benz to establish the exact
ranking of hand washing versus machine washing of vehicles relative to
damage to paintwork.
To make the test as realistic as
possible, typical family sedans were used - with a few hundred miles on
the odometer. It was stipulated that each car was to receive the
equivalent of one year's wash stress (about 25 washes) - some cars by
hand washing methods, others by automatic carwashing equipment.
To make the test as realistic as
possible, and to give both the hand washers and the automatic carwashing
equipment something to get clean, five test vehicles were thoroughly
coated with a mixture of street dirt, under-fender dirt accumulations,
oily water, and thawing-salt residue. This test mixture, inspected under
a microscope, contained grit particles measuring between 0.5mm and 1.0mm
which are enough to damage the toughest paintwork if not carefully
removed.
The Hand Wash
Without having been told the why's
or the wherefore's, four men were given the chore of washing four of the
test cars by hand. Each person was to do as thorough a job as possible.
Since there were four people involved, and since each person used their
favorite "tools", together they presented a cross-section of various
hand washing techniques commonly used by average car owners.
So the marathon carwash began. The
four men showed up in four different sections of town enthusiastically
sponging and lathering their test cars as if they were their very own.
Bystanders could see one man hard at work in a do-it-yourself
self-service type of car wash with high-pressure water facilities;
another was busy at home with the garden hose and a water spray-brush.
One man scrubbed away utilizing a bucket, a sponge, and a garden hose.
One, to the horror of the environmentalists, and in defiance of local
regulations, washed his test car at a lakeside.
The Automatic Wash
As the alternative to the
perspiring hand washers, automatic carwashing equipment was used to wash
the fifth test car. To keep the test above board, the test vehicle
arrived unannounced during the hours when the car wash was open for
business. The car was washed along with other cars.
The Examination
To measure the extent of paintwork
damage, microscopes were available. However, pure reflecting microscopy,
as well as electron microscopy results merely in a visual picture of
scratches. A comparable measure of true depth cannot thus be achieved.
Consequently, a method of analysis was used which could determine the
exact depth of the scratches and grooves, namely, the
interference-microscopic analysis method.
This method allows the glossy
surface, with all of its irregularities to appear like a relief map. An
interference band is created and corresponds to the contours. Band
distances are 0.27 of one thousandth of a millimeter, thereby allowing
even the tiniest grooves and scratches on the gloss to be accurately
measured and compared.
The Result
The comparison tests produced
results of which every car owner should be aware. Automatic car washing
and hand washing have completely different effects on automobile paint.
How does the paintwork of a car
appear after 25 washes - equivalent of a year's worth of washing?
The results are depressing, at
least to the car owner who, up to now, has firmly believed in hand
washing. The deepest scratches after hand washing had a depth of more
than one-tenth of the paint surface. Under the microscope, the paintwork
looked like a cratered landscape. The paintwork was deeply scored and
scratched - the result of dirt and trapped sand particles.
In
hand washing, invariably too little water is used. Even with a garden
hose and a sponge technique, small sand particles lodge themselves
firmly in the fine pores of the sponge or wash mitt and cannot be
removed even by good rinsing. Such particles work on the paint surface
like sanding discs. Furthermore, the hand washings produced a tangle of
uneven scratches in the paint surface.
By comparison, the surfaces of the
test vehicle washed with automatic carwashing equipment appeared
different. Compared with the hand washed surfaces, it was remarkably
smooth, with many very fine markings virtually parallel and uniform -
less than .0003mm - the result of evenly moving and rotating cloth pads
and curtains. The machine-washed surfaces were in very good condition
after 25 washes.
Wash a car by hand or by machine,
in either case, it looks immaculate right after the wash. The
sophisticated test described suggests that looks are deceiving: The
paintwork on a car washed by automatic carwashing equipment is in much
better condition than one washed by hand - even though the car owner
lavishes tender, loving care on their vehicle.
Eventually, either by force of
habit or because the car finish looks dull, the weekend hand washer
resorts to the lengthy and back-breaking chore of applying abrasive
rubbing compound or similar pastes and liquids to their vehicle. This
process indeed restores the luster to the finish. Such "pampered" cars
naturally appear to have just rolled out of the showroom. The proud
motorist forgets the long hours with the rubbing compound, and is
probably unaware that the reason for all that work (to get the scratches
out) was their energetic hand washing procedure on previous weekends.
On the other hand, the motorist
who uses the services of a professional car wash with their automatic
carwashing equipment subjects the paintwork of their vehicle to the
thorough, but gentle action of cloth pads and curtains which treat their
paint job with tender, loving care. Knowing that the car finish has to
have some protection against the ravages of the chemicals in the air and
to also provide a barrier of protection against bird droppings and other
contaminants, this car owner will periodically apply a coat of wax to
their vehicle. At that moment, their car looks as if it had just rolled
out of the showroom.
In
comparison, although both cars after washing and other treatment will
look pretty much the same, a car is actually treated better (especially
concerning the paint finish) by machine washing at a professional car
wash and the application of wax than a car washed by hand (with the
resulting need for the application of rubbing compounds, etc.). However,
in the process, the car owner who utilized the services of a
professional car wash has saved a great deal of time, labor, and effort. |
